Question

2.00 g of NaOH are dissolved in water to make 4.00 L of solution. What is the concentration of hydronium ions, [H3O+], in this solution?

a) 0.5 M
b) 1.0 M
c) 1.5 M
d) 2.0 M

Answer 1

The concentration of hydronium ions in the solution can be calculated using the formula: concentration (M) = moles / volume (L). The concentration of hydronium ions is 0.013 M.

Step-by-step explanation:

The concentration of hydronium ions, [H3O+], in the solution can be calculated using the formula:

concentration (M) = moles / volume (L)

To find the moles of NaOH, we need to convert the mass to moles using the molar mass:

molar mass NaOH = 22.99 g/mol (Na) + 16.00 g/mol (O) + 1.01 g/mol (H) = 39.00 g/mol

moles NaOH = mass NaOH / molar mass NaOH = 2.00 g / 39.00 g/mol = 0.051 mol

Therefore, the concentration of hydronium ions is:
[H3O+] = 0.051 mol / 4.00 L = 0.013 M

Therefore, the answer is option (a) 0.5 M.